The invention relates to complementary metal oxide semiconductor (CMOS) structures as they exist in monolithic integrated circuit (IC) device. It would be useful to be able to program the gain, or transconductance, of operational amplifiers (op amps) by means of a resistor that is external to the IC chip and not subject to the variations in supply voltage or variations in device parameters that commonly accompany the fabrication process. Such an op amp could be referred to as a transconductance amplifier or G.sub.m amp.
In my copending application Ser. No. 460,325 filed Jan. 24, 1983, now U.S. Pat. No. 4,459,555 and titled MOS Differential Amplifier Gain Control Circuit, a circuit is disclosed for varying the gain of an op amp in response to a control voltage. The teaching in that application is incorporated herein by reference.